This application claims the priority of Korean Patent Application No. 2002-76034, filed on Dec. 2, 2002, in the Korean Intellectual Property Office, the disclosure of which is incorporated herein in its entirety by reference.
1. Field of the Invention
The present invention relates to a method of processing a broadcasting signal, and more particularly, to a method of detecting a change in a broadcasting table indicating broadcasting information from cyclic redundancy check (CRC) data of section information of a broadcasting stream.
2. Description of the Related Art
Digital televisions (DTVs) obtain a variety of tables by parsing sections of Program Specific Information (PSI: channel information or an information table with an ID of video or audio), which is a standard of the Motion Picture Expert Group (MPEG), or sections of a Program and System Information Protocol (PSIP), which is a standard of the Advanced Television System Committee (ATSC). The DTVs perform various functions using video, audio, electronic program guide (EPG), time, and channel information included in the variety of tables. Here, sections to which the tables belong are repeatedly input from a broadcasting stream and use a 5-bit version number to determine whether a currently input table is a parsed table. In a case where the version number is not changed in spite of changes in contents of the tables or broadcasting streams with the same version number are consecutively input, the DTVs may not work properly.
FIG. 1 is a flowchart explaining a method of detecting a change in a broadcasting table according to the prior art. Referring to FIG. 1, in step 100, information on a version of a table header is read. In step 101, a determination is made as to whether the version is new or updated. If in step 101, it is determined that the version is new or updated, in step 102, the table is parsed, and then in step 103, the table is updated.
A version of a table basically indicates whether data of a new version of a table is different from data of a previous version of a table, i.e., data of a table is changed. Thus, the determination as to whether the table is changed is generally made using the version. However, since the version is composed of 5 bits in a section, the same version occurs in every 32 bits of the section. A virtual version number is mainly 0, 1, 2, or the like. Thus, when the broadcasting stream is changed to be broadcast, the same version of the broadcasting stream may be broadcast. In addition, since DTVs have just been introduced, a broadcasting station sometimes transmits wrong data or does not change the version even when contents of the table are changed. In this case, a TV screen is not displayed or malfunctions.